python-edsdk-ctypes

Pure-ctypes Python wrapper for the Canon EDSDK (EOS Digital Software Development Kit).

• Cross-platform: macOS, Linux, Windows — single codebase, no C++ extension to compile.
• Python 3.12+.
• No build step: ships as a normal pure-Python package.
• Designed for use cases like live-view streaming, QR / fiducial detection, remote shooting, exposure control, and multi-camera setups.

Status: alpha. Public API is subject to change until 0.1.0.

Distribution: PyPI as edsdk-ctypes — import edsdk.

Why another EDSDK wrapper?

The existing edsdk-python is a CPython C++ extension and works on Windows only. This project takes a different approach:

The Python-side IntEnum constants under src/edsdk/constants/_generated.py are produced mechanically from the EDSDK header by tools/gen_constants.py. Re-run that script when upgrading to a newer EDSDK release.

EDSDK is NOT included

Canon distributes the EDSDK under NDA. You must obtain it yourself via the Canon Developer Program for your region:

• Canon Japan
• Canon Europe
• Canon Americas
• Canon Asia

This package only ships Python bindings. No EDSDK headers, libraries, or binaries are redistributed.

Installation

pip install edsdk-ctypes

Then place the EDSDK library where the loader can find it. The loader searches in this order:

1. EDSDK_LIBRARY_PATH environment variable (path to the shared library file or its containing directory)
2. Standard system search paths (LD_LIBRARY_PATH on Linux, DYLD_LIBRARY_PATH on macOS, PATH on Windows)

Per-platform expectations:

Quick start

import edsdk
from edsdk import PropID, SaveTo

with edsdk.SDK():
    cameras = edsdk.list_cameras()
    print(f"Found {len(cameras)} camera(s)")
    for cam in cameras:
        info = cam.device_info()
        print(f"  {info.device_description} via {info.port_name}")
        with cam:
            print("  ISO:", cam.get_property(PropID.ISOSpeed))
            cam.set_property(PropID.SaveTo, int(SaveTo.Host))
            cam.set_capacity()

Live view + capture

with edsdk.SDK():
    cam = edsdk.list_cameras()[0]
    with cam, edsdk.LiveView(cam) as lv:
        jpeg_bytes = lv.frame()      # returns a JPEG frame

def on_object(event, handle):
    if event == edsdk.ObjectEvent.DirItemRequestTransfer:
        edsdk.Camera.download_to_file(handle, "captures/")
        edsdk.Camera.release_handle(handle)

with edsdk.SDK():
    cam = edsdk.list_cameras()[0]
    with cam:
        cam.on_object_event(on_object)
        cam.set_property(edsdk.PropID.SaveTo, int(edsdk.SaveTo.Host))
        cam.set_capacity()
        cam.take_picture()

See examples/ for full runnable samples:

Notes for R-series bodies (R / RP / R3 / R5 / R6 / R8 / ...)

Verified against an EOS R3 (firmware 1.7.1), some quirks worth knowing:

• Capture requires live view to be active. Without Evf_OutputDevice having the PC bit set, PressShutterButton is rejected with EDS_ERR_PARTIAL_DELETION. The high-level Camera.take_picture drives UILock → PressShutter → UIUnLock, but you must wrap the call in a :class:LiveView context (see examples/take_picture.py).
• The legacy CameraCommand.TakePicture opcode is not accepted — R-bodies require PressShutterButton. Camera.take_picture() uses the modern flow.
• An SD card must be inserted even with SaveTo.Host — the body stages the file on card before transfer. Without a card, capture fails with PARTIAL_DELETION.
• UILock must use param=0. param=1 (TFT off) drops the USB connection on R3 (subsequent calls return DEVICE_NOT_FOUND).
• Property changes need a small settle delay (~500 ms) before the next PressShutterButton. Without it, R3 returns PARTIAL_DELETION.
• All EDSDK calls must run on the same thread. Don't pump events from a worker thread while the main thread issues commands — that corrupts SDK state. Use edsdk.pump_events(...) / edsdk.wait_until(...) from the thread that owns the SDK.

Roadmap

• Library loader (Linux / macOS / Windows) with EDSDK_LIBRARY_PATH override
• EdsInitializeSDK / EdsTerminateSDK / EdsGetEvent + pump_events / wait_until (single-thread)
• Camera enumeration, OpenSession / CloseSession, GetDeviceInfo
• Property get/set with type-aware marshalling (incl. Time, Rational, Rect, FocusInfo, PictureStyleDesc)
• Object / Property / State / CameraAdded event handlers
• TakePicture + download flow (Camera.download_to_file)
• Live-view (EvfImageRef) → bytes
• High-level Camera class encapsulating the above
• Numpy / OpenCV zero-copy decoding helper
• Property descriptor → human-readable shutter / aperture / ISO mapping
• Windows COM message-pump helper (parallel to pump_events)
• Smoke-test suite that runs against an attached body in CI

Regenerating constants for a new SDK

src/edsdk/constants/_generated.py is produced mechanically from the EDSDK header by tools/gen_constants.py. Re-run it whenever you bump to a newer SDK release.

pipenv run python tools/gen_constants.py \
    /path/to/EDSDK/Header/EDSDKTypes.h \
    -o src/edsdk/constants/_generated.py
git diff src/edsdk/constants/_generated.py   # review additions / removals
pipenv run pytest -q                         # confirm nothing broke

That single output file is everything that ships — edsdk.constants re-exports its IntEnum classes automatically, so the public API (edsdk.PropID, edsdk.CameraCommand, …) updates with no further edits.

How the conversion works

gen_constants.py reads EDSDKTypes.h directly (no preprocessor) and recognises two header conventions:

Naming rules:

• Macro groups are emitted under the bare group name (PropID, CameraCommand, CameraStatusCommand, ObjectEvent, PropertyEvent, StateEvent). Member names keep the suffix after the prefix (kEdsPropID_Evf_OutputDevice → PropID.Evf_OutputDevice).
• Typedef enums drop the leading Eds from the type name (EdsSaveTo → SaveTo, EdsAccess → Access). The longest common prefix shared by all members is stripped to leave clean names (kEdsAccess_Read → Access.Read).
• Members starting with a digit are prefixed with _; members that collide with Python keywords get a trailing _. Duplicate names (occasionally produced by header aliasing) are de-duplicated, keeping the first occurrence.

Constant-expression support during parsing:

• Integer literals in decimal or hex, optionally with the L suffix.
• References to earlier members in the same enum (Both = Camera | Host).
• Bitwise operators (|, &, ^, <<, >>), arithmetic (+, -, *, /), and parentheses. Anything outside this safelist (string literals, function calls, etc.) is rejected with a clear error.
• Members without an explicit = value continue from the previous member +1 — matching C enum semantics.

Things the generator does NOT cover

• Av / Tv / ISO speed value tables — these aren't in the header. They live in Document/EDSDK_API_*.pdf. Use Camera.get_property_desc(PropID.ISOSpeed) on a real body to enumerate the values supported by that camera.
• Error code names — handled separately in src/edsdk/errors.py (parsed from EDSDKErrors.h mentally, not from a generator).
• Struct layouts — defined by hand in src/edsdk/_types.py since they need ctypes-specific scalar choices.

License

MIT — see LICENSE.